webmcp: c343ce9092ee libraries/mondelefant/mondelefant.lua

146 Sets selector to empty list mode. The selector is modified and returned. When using the selector, no SQL query will be issued, but instead an empty database result list is returned.

147

148 --]]--

149 function selector_prototype:empty_list_mode()

150 self._mode = "empty_list"

151 return self

152 end

153 --//--

154

155 --[[--

156 db_selector =

157 <db_selector>:add_with(

158 expression = expression,

159 selector = selector

160 )

161

162 Adds an WITH RECURSIVE expression to the selector. The selector is modified and returned.

163 --]]--

164 function selector_prototype:add_with(expression, selector)

165 add(self._with, {"$ AS ($)", {expression}, {selector}})

166 return self

167 end

168 --//--

169

170 --[[--

171 db_selector = -- same selector returned

172 <db_selector>:add_distinct_on(

173 expression -- expression as passed to "assemble_command"

174 )

175

176 Adds an DISTINCT ON expression to the selector. The selector is modified and returned.

177

178 --]]--

179 function selector_prototype:add_distinct_on(expression)

180 if self._distinct then

181 error("Can not combine DISTINCT with DISTINCT ON.")

182 end

183 add(self._distinct_on, expression)

184 return self

185 end

186 --//--

187

188 --[[--

189 db_selector = -- same selector returned

190 <db_selector>:set_distinct()

191

192 Sets selector to perform a SELECT DISTINCT instead of SELECT (ALL). The selector is modified and returned. This mode can not be combined with DISTINCT ON.

193

194 --]]--

195 function selector_prototype:set_distinct()

196 if #self._distinct_on > 0 then

197 error("Can not combine DISTINCT with DISTINCT ON.")

198 end

199 self._distinct = true

200 return self

201 end

202 --//--

203

204 --[[--

205 db_selector = -- same selector returned

206 <db_selector>:add_from(

207 expression, -- expression as passed to "assemble_command"

208 alias, -- optional alias expression as passed to "assemble_command"

209 condition -- optional condition expression as passed to "assemble_command"

210 )

211

212 Adds expressions for FROM clause to the selector. The selector is modified and returned. If an additional condition is given, an INNER JOIN will be used, otherwise a CROSS JOIN.

213

214 This method is identical to "join".

215

216 --]]--

217 function selector_prototype:add_from(expression, alias, condition)

218 local first = (#self._from == 0)

219 if not first then

220 if condition then

221 add(self._from, "INNER JOIN")

222 else

223 add(self._from, "CROSS JOIN")

224 end

225 end

226 if getmetatable(expression) == selector_metatable then

227 if alias then

228 add(self._from, {'($) AS "$"', {expression}, {alias}})

229 else

230 add(self._from, {'($) AS "subquery"', {expression}})

231 end

232 else

233 if alias then

234 add(self._from, {'$ AS "$"', {expression}, {alias}})

235 else

236 add(self._from, expression)

237 end

238 end

239 if condition then

240 if first then

241 self:add_where(condition)

242 else

243 add(self._from, "ON")

244 add(self._from, condition)

245 end

246 end

247 return self

248 end

249 --//--

250

251 --[[--

252 db_selector = -- same selector returned

253 <db_selector>:add_where(

254 expression -- expression as passed to "assemble_command"

255 )

256

257 Adds expressions for WHERE clause to the selector. The selector is modified and returned. Multiple calls cause expressions to be AND-combined.

258

259 --]]--

260 function selector_prototype:add_where(expression)

261 add(self._where, expression)

262 return self

263 end

264 --//--

265

266 --[[--

267 db_selector = -- same selector returned

268 <db_selector>:add_group_by(

269 expression -- expression as passed to "assemble_command"

270 )

271

272 Adds expressions for GROUP BY clause to the selector. The selector is modified and returned.

273

274 --]]--

275 function selector_prototype:add_group_by(expression)

276 add(self._group_by, expression)

277 return self

278 end

279 --//--

280

281 --[[--

282 db_selector = -- same selector returned

283 <db_selector>:add_having(

284 expression -- expression as passed to "assemble_command"

285 )

286

287 Adds expressions for HAVING clause to the selector. The selector is modified and returned. Multiple calls cause expressions to be AND-combined.

288

289 --]]--

290 function selector_prototype:add_having(expression)

291 add(self._having, expression)

292 return self

293 end

294 --//--

295

296 --[[--

297 db_selector = -- same selector returned

298 <db_selector>:add_combine(

299 expression -- expression as passed to "assemble_command"

300 )

301

302 This function is used for UNION/INTERSECT/EXCEPT clauses. It does not need to be called directly. Use "union", "union_all", "intersect", "intersect_all", "except" and "except_all" instead.

303

304 --]]--

305 function selector_prototype:add_combine(expression)

306 add(self._combine, expression)

307 return self

308 end

309 --//--

310

311 --[[--

312 db_selector = -- same selector returned

313 <db_selector>:add_order_by(

314 expression -- expression as passed to "assemble_command"

315 )

316

317 Adds expressions for ORDER BY clause to the selector. The selector is modified and returned.

318

319 --]]--

320 function selector_prototype:add_order_by(expression)

321 add(self._order_by, expression)

322 return self

323 end

324 --//--

325

326 --[[--

327 db_selector = -- same selector returned

328 <db_selector>:limit(

329 count -- integer used as LIMIT

330 )

331

332 Limits the number of rows to a given number, by using LIMIT. The selector is modified and returned.

333

334 --]]--

335 function selector_prototype:limit(count)

336 if type(count) ~= "number" or count % 1 ~= 0 then

337 error("LIMIT must be an integer.")

338 end

339 self._limit = count

340 return self

341 end

342 --//--

343

344 --[[--

345 db_selector = -- same selector returned

346 <db_selector>:offset(

347 count -- integer used as OFFSET

348 )

349

350 Skips a given number of rows, by using OFFSET. The selector is modified and returned.

351

352 --]]--

353 function selector_prototype:offset(count)

354 if type(count) ~= "number" or count % 1 ~= 0 then

355 error("OFFSET must be an integer.")

356 end

357 self._offset = count

358 return self

359 end

360 --//--

361

362 --[[--

363 db_selector = -- same selector returned

364 <db_selector>:for_share()

365

366 Adds FOR SHARE to the statement, to share-lock all rows read. The selector is modified and returned.

367

368 --]]--

369 function selector_prototype:for_share()

370 self._read_lock.all = true

371 return self

372 end

373 --//--

374

375 --[[--

376 db_selector = -- same selector returned

377 <db_selector>:for_share_of(

378 expression -- expression as passed to "assemble_command"

379 )

380

381 Adds FOR SHARE OF to the statement, to share-lock all rows read by the named table(s). The selector is modified and returned.

382

383 --]]--

384 function selector_prototype:for_share_of(expression)

385 add(self._read_lock, expression)

386 return self

387 end

388 --//--

389

390 --[[--

391 db_selector = -- same selector returned

392 <db_selector>:for_update()

393

394 Adds FOR UPDATE to the statement, to exclusivly lock all rows read. The selector is modified and returned.

395

396 --]]--

397 function selector_prototype:for_update()

398 self._write_lock.all = true

399 return self

400 end

401 --//--

402

403 --[[--

404 db_selector = -- same selector returned

405 <db_selector>:for_update_of(

406 expression -- expression as passed to "assemble_command"

407 )

408

409 Adds FOR SHARE OF to the statement, to exclusivly lock all rows read by the named table(s). The selector is modified and returned.

410

411 --]]--

412 function selector_prototype:for_update_of(expression)

413 add(self._write_lock, expression)

414 return self

415 end

416 --//--

417

418 --[[--

419 db_selector = -- same selector returned

420 <db_selector>:reset_fields()

421

422 This method removes all fields added by method "add_field". The selector is modified and returned.

423

424 --]]--

425 function selector_prototype:reset_fields()

426 for idx in ipairs(self._fields) do

427 self._fields[idx] = nil

428 end

429 return self

430 end

431 --//--

432

433 --[[--

434 db_selector = -- same selector returned

435 <db_selector>:add_field(

436 expression, -- expression as passed to "assemble_command"

437 alias, -- optional alias expression as passed to "assemble_command"

438 option_list -- optional list of options (may contain strings "distinct" or "grouped")

439 )

440

441 Adds fields to the selector. The selector is modified and returned. The third argument can be a list of options. If option "distinct" is given, then "add_distinct_on" will be executed for the given field or alias. If option "grouped" is given, then "add_group_by" will be executed for the given field or alias.

442

443 --]]--

444 function selector_prototype:add_field(expression, alias, options)

445 if alias then

446 add(self._fields, {'$ AS "$"', {expression}, {alias}})

447 else

448 add(self._fields, expression)

449 end

450 if options then

451 for i, option in ipairs(options) do

452 if option == "distinct" then

453 if alias then

454 self:add_distinct_on('"' .. alias .. '"')

455 else

456 self:add_distinct_on(expression)

457 end

458 elseif option == "grouped" then

459 if alias then

460 self:add_group_by('"' .. alias .. '"')

461 else

462 self:add_group_by(expression)

463 end

464 else

465 error("Unknown option '" .. option .. "' to add_field method.")

466 end

467 end

468 end

469 return self

470 end

471 --//--

472

473 --[[--

474 db_selector = -- same selector returned

475 <db_selector>:join(

476 expression, -- expression as passed to "assemble_command"

477 alias, -- optional alias expression as passed to "assemble_command"

478 condition -- optional condition expression as passed to "assemble_command"

479 )

480

481 Adds expressions for FROM clause to the selector. The selector is modified and returned. If an additional condition is given, an INNER JOIN will be used, otherwise a CROSS JOIN.

482

483 This method is identical to "add_from".

484

485 --]]--

486 function selector_prototype:join(...) -- NOTE: alias for add_from

487 return self:add_from(...)

488 end

489 --//--

490

491 --[[--

492 db_selector = -- same selector returned

493 <db_selector>:from(

494 expression, -- expression as passed to "assemble_command"

495 alias, -- optional alias expression as passed to "assemble_command"

496 condition -- optional condition expression as passed to "assemble_command"

497 )

498

499 Adds the first expression for FROM clause to the selector. The selector is modified and returned. If an additional condition is given, an INNER JOIN will be used, otherwise a CROSS JOIN.

500

501 This method is identical to "add_from" or "join", except that an error is thrown, if there is already any FROM expression existent.

502

503 --]]--

504 function selector_prototype:from(expression, alias, condition)

505 if #self._from > 0 then

506 error("From-clause already existing (hint: try join).")

507 end

508 return self:join(expression, alias, condition)

509 end

510 --//--

511

512 --[[--

513 db_selector = -- same selector returned

514 <db_selector>:left_join(

515 expression, -- expression as passed to "assemble_command"

516 alias, -- optional alias expression as passed to "assemble_command"

517 condition -- optional condition expression as passed to "assemble_command"

518 )

519

520 Adds expressions for FROM clause to the selector using a LEFT OUTER JOIN. The selector is modified and returned.

521

522 --]]--

523 function selector_prototype:left_join(expression, alias, condition)

524 local first = (#self._from == 0)

525 if not first then

526 add(self._from, "LEFT OUTER JOIN")

527 end

528 if alias then

529 add(self._from, {'$ AS "$"', {expression}, {alias}})

530 else

531 add(self._from, expression)

532 end

533 if condition then

534 if first then

535 self:add_where(condition)

536 else

537 add(self._from, "ON")

538 add(self._from, condition)

539 end

540 end

541 return self

542 end

543 --//--

544

545 --[[--

546 db_selector = -- same selector returned

547 <db_selector>:union(

548 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE

549 )

550

551 This method adds a UNION clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.

552

553 --]]--

554 function selector_prototype:union(expression)

555 self:add_combine{"UNION $", {expression}}

556 return self

557 end

558 --//--

559

560 --[[--

561 db_selector = -- same selector returned

562 <db_selector>:union_all(

563 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE

564 )

565

566 This method adds a UNION ALL clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.

567

568 --]]--

569 function selector_prototype:union_all(expression)

570 self:add_combine{"UNION ALL $", {expression}}

571 return self

572 end

573 --//--

574

575 --[[--

576 db_selector = -- same selector returned

577 <db_selector>:intersect(

578 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE

579 )

580

581 This method adds an INTERSECT clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.

582

583 --]]--

584 function selector_prototype:intersect(expression)

585 self:add_combine{"INTERSECT $", {expression}}

586 return self

587 end

588 --//--

589

590 --[[--

591 db_selector = -- same selector returned

592 <db_selector>:intersect_all(

593 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE

594 )

595

596 This method adds an INTERSECT ALL clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.

597

598 --]]--

599 function selector_prototype:intersect_all(expression)

600 self:add_combine{"INTERSECT ALL $", {expression}}

601 return self

602 end

603 --//--

604

605 --[[--

606 db_selector = -- same selector returned

607 <db_selector>:except(

608 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE

609 )

610

611 This method adds an EXCEPT clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.

612

613 --]]--

614 function selector_prototype:except(expression)

615 self:add_combine{"EXCEPT $", {expression}}

616 return self

617 end

618 --//--

619

620 --[[--

621 db_selector = -- same selector returned

622 <db_selector>:except_all(

623 expression -- expression or selector without ORDER BY, LIMIT, FOR UPDATE or FOR SHARE

624 )

625

626 This method adds an EXCEPT ALL clause to the given selector. The selector is modified and returned. The selector (or expression) passed as argument to this function shall not contain any ORDER BY, LIMIT, FOR UPDATE or FOR SHARE clauses.

627

628 --]]--

629 function selector_prototype:except_all(expression)

630 self:add_combine{"EXCEPT ALL $", {expression}}

631 return self

632 end

633 --//--

634

635 --[[--

636 db_selector = -- same selector returned

637 <db_selector>:set_class(

638 class -- database class (model)

639 )

640

641 This method makes the selector to return database result lists or objects of the given database class (model). The selector is modified and returned.

642

643 --]]--

644 function selector_prototype:set_class(class)

645 self._class = class

646 return self

647 end

648 --//--

649

650 --[[--

651 db_selector = -- same selector returned

652 <db_selector>:attach(

653 mode, -- attachment type: "11" one to one, "1m" one to many, "m1" many to one

654 data2, -- other database result list or object, the results of this selector shall be attached with

655 field1, -- field name(s) in result list or object of this selector used for attaching

656 field2, -- field name(s) in "data2" used for attaching

657 ref1, -- name of reference field in the results of this selector after attaching

658 ref2 -- name of reference field in "data2" after attaching

659 )

660

661 This method causes database result lists or objects of this selector to be attached with other database result lists after execution. This method does not need to be called directly.

662

663 --]]--

664 function selector_prototype:attach(mode, data2, field1, field2, ref1, ref2)

665 self._attach = {

666 mode = mode,

667 data2 = data2,

668 field1 = field1,

669 field2 = field2,

670 ref1 = ref1,

671 ref2 = ref2

672 }

673 return self

674 end

675 --//--

676

677 function selector_metatable:__tostring()

678 local parts = {sep = " "}

679 if #self._with > 0 then

680 add(parts, {"WITH RECURSIVE $", self._with})

681 end

682 add(parts, "SELECT")

683 if self._distinct then

684 add(parts, "DISTINCT")

685 elseif #self._distinct_on > 0 then

686 add(parts, {"DISTINCT ON ($)", self._distinct_on})

687 end

688 add(parts, {"$", self._fields})

689 if #self._from > 0 then

690 add(parts, {"FROM $", self._from})

691 end

692 if #self._mode == "empty_list" then

693 add(parts, "WHERE FALSE")

694 elseif #self._where > 0 then

695 add(parts, {"WHERE ($)", self._where})

696 end

697 if #self._group_by > 0 then

698 add(parts, {"GROUP BY $", self._group_by})

699 end

700 if #self._having > 0 then

701 add(parts, {"HAVING ($)", self._having})

702 end

703 for i, v in ipairs(self._combine) do

704 add(parts, v)

705 end

706 if #self._order_by > 0 then

707 add(parts, {"ORDER BY $", self._order_by})

708 end

709 if self._mode == "empty_list" then

710 add(parts, "LIMIT 0")

711 elseif self._mode ~= "list" then

712 add(parts, "LIMIT 1")

713 elseif self._limit then

714 add(parts, "LIMIT " .. self._limit)

715 end

716 if self._offset then

717 add(parts, "OFFSET " .. self._offset)

718 end

719 if self._write_lock.all then

720 add(parts, "FOR UPDATE")

721 else

722 if self._read_lock.all then

723 add(parts, "FOR SHARE")

724 elseif #self._read_lock > 0 then

725 add(parts, {"FOR SHARE OF $", self._read_lock})

726 end

727 if #self._write_lock > 0 then

728 add(parts, {"FOR UPDATE OF $", self._write_lock})

729 end

730 end

731 return self._db_conn:assemble_command{"$", parts}

732 end

733

734 --[[--

735 db_error, -- database error object, or nil in case of success

736 result = -- database result list or object

737 <db_selector>:try_exec()

738

739 This method executes the selector on its database. First return value is an error object or nil in case of success. Second return value is the result list or object.

740

741 --]]--

742 function selector_prototype:try_exec()

743 if self._mode == "empty_list" then

744 if self._class then

745 return nil, self._class:create_list()

746 else

747 return nil, self._db_conn:create_list()

748 end

749 end

750 local db_error, db_result = self._db_conn:try_query(self, self._mode)

751 if db_error then

752 return db_error

753 elseif db_result then

754 if self._class then set_class(db_result, self._class) end

755 if self._attach then

756 attach(

757 self._attach.mode,

758 db_result,

759 self._attach.data2,

760 self._attach.field1,

761 self._attach.field2,

762 self._attach.ref1,

763 self._attach.ref2

764 )

765 end

766 return nil, db_result

767 else

768 return nil

769 end

770 end

771 --//--

772

773 --[[--

774 result = -- database result list or object

775 <db_selector>:exec()

776

777 This method executes the selector on its database. The result list or object is returned on success, otherwise an error is thrown.

778

779 --]]--

780 function selector_prototype:exec()

781 local db_error, result = self:try_exec()

782 if db_error then

783 db_error:escalate()

784 else

785 return result

786 end

787 end

788 --//--

789

790 --[[--

791 count = -- number of rows returned

792 <db_selector>:count()

793

794 This function wraps the given selector inside a subquery to count the number of rows returned by the database. NOTE: The result is cached inside the selector, thus the selector should NOT be modified afterwards.

795

796 --]]--

797 function selector_prototype:count()

798 if not self._count then

799 local count_selector = self:get_db_conn():new_selector()

800 count_selector:add_field('count(1)')

801 count_selector:add_from(self)

802 count_selector:single_object_mode()

803 self._count = count_selector:exec().count

804 end

805 return self._count

806 end

807 --//--

808

809

810

811 -----------------

812 -- attachments --

813 -----------------

814

815 local function attach_key(row, fields)

816 local t = type(fields)

817 if t == "string" then

818 return tostring(row[fields])

819 elseif t == "table" then

820 local r = {}

821 for idx, field in ipairs(fields) do

822 r[idx] = string.format("%q", row[field])

823 end

824 return table.concat(r)

825 else

826 error("Field information for 'mondelefant.attach' is neither a string nor a table.")

827 end

828 end

829

830 --[[--

831 mondelefant.attach(

832 mode, -- attachment type: "11" one to one, "1m" one to many, "m1" many to one

833 data1, -- first database result list or object

834 data2, -- second database result list or object

835 key1, -- field name(s) in first result list or object used for attaching

836 key2, -- field name(s) in second result list or object used for attaching

837 ref1, -- name of reference field to be set in first database result list or object

838 ref2 -- name of reference field to be set in second database result list or object

839 )

840

841 This function attaches database result lists/objects with each other. It does not need to be called directly.

842

843 --]]--

844 function attach(mode, data1, data2, key1, key2, ref1, ref2)

845 local many1, many2

846 if mode == "11" then

847 many1 = false

848 many2 = false

849 elseif mode == "1m" then

850 many1 = false

851 many2 = true

852 elseif mode == "m1" then

853 many1 = true

854 many2 = false

855 elseif mode == "mm" then

856 many1 = true

857 many2 = true

858 else

859 error("Unknown mode specified for 'mondelefant.attach'.")

860 end

861 local list1, list2

862 if data1._type == "object" then

863 list1 = { data1 }

864 elseif data1._type == "list" then

865 list1 = data1

866 else

867 error("First result data given to 'mondelefant.attach' is invalid.")

868 end

869 if data2._type == "object" then

870 list2 = { data2 }

871 elseif data2._type == "list" then

872 list2 = data2

873 else

874 error("Second result data given to 'mondelefant.attach' is invalid.")

875 end

876 local hash1 = {}

877 local hash2 = {}

878 if ref2 then

879 for i, row in ipairs(list1) do

880 local key = attach_key(row, key1)

881 local list = hash1[key]

882 if not list then list = {}; hash1[key] = list end

883 list[#list + 1] = row

884 end

885 end

886 if ref1 then

887 for i, row in ipairs(list2) do

888 local key = attach_key(row, key2)

889 local list = hash2[key]

890 if not list then list = {}; hash2[key] = list end

891 list[#list + 1] = row

892 end

893 for i, row in ipairs(list1) do

894 local key = attach_key(row, key1)

895 local matching_rows = hash2[key]

896 if many2 then

897 local list = data2._connection:create_list(matching_rows)

898 list._class = data2._class

899 row._ref[ref1] = list

900 elseif matching_rows and #matching_rows == 1 then

901 row._ref[ref1] = matching_rows[1]

902 else

903 row._ref[ref1] = false

904 end

905 end

906 end

907 if ref2 then

908 for i, row in ipairs(list2) do

909 local key = attach_key(row, key2)

910 local matching_rows = hash1[key]

911 if many1 then

912 local list = data1._connection:create_list(matching_rows)

913 list._class = data1._class

914 row._ref[ref2] = list

915 elseif matching_rows and #matching_rows == 1 then

916 row._ref[ref2] = matching_rows[1]

917 else

918 row._ref[ref2] = false

919 end

920 end

921 end

922 end

923 --//--

924

925

926

927 ------------------

928 -- model system --

929 ------------------

930

931 --[[--

932 <db_class>.primary_key

933

934 Primary key of a database class (model). Defaults to "id".

935

936 If the primary key is a tuple, then a sequence (table with integer keys mapped to the column names) must be used. If the primary key is contained in a JSON document within a table column, then a special object with the following fields is expected: {json_doc = "column_name", key = "field_name_within_json_object", type = "postgresql_type"}.

937

938 --]]--

939 class_prototype.primary_key = "id"

940 --//--

941

942 --[[--

943 <db_class>.document_column

944

945 Optional column name to redirect key lookups to. This can be used to allow for an easier access to fields of a JSON document.

946

947 --]]--

948 class_prototype.document_column = nil

949 --//--

950

951 --[[--

952 db_handle = -- database connection handle used by this class

953 <db_class>:get_db_conn()

954

955 By implementing this method for a particular model or overwriting it in the default prototype "mondelefant.class_prototype", classes are connected with a particular database. This method needs to return a database connection handle. If it is not overwritten, an error is thrown, when invoking this method.

956

957 --]]--

958 function class_prototype:get_db_conn()

959 error(

960 "Method mondelefant class(_prototype):get_db_conn() " ..

961 "has to be implemented."

962 )

963 end

964 --//--

965

966 --[[--

967 string = -- string of form '"schemaname"."tablename"' or '"tablename"'

968 <db_class>:get_qualified_table()

969

970 This method returns a string with the (double quoted) qualified table name used to store objects of this class.

971

972 --]]--

973 function class_prototype:get_qualified_table()

974 if not self.table then error "Table unknown." end

975 if self.schema then

976 return '"' .. self.schema .. '"."' .. self.table .. '"'

977 else

978 return '"' .. self.table .. '"'

979 end

980 end

981 --]]--

982

983 --[[--

984 string = -- single quoted string of form "'schemaname.tablename'" or "'tablename'"

985 <db_class>:get_qualified_table_literal()

986

987 This method returns a string with an SQL literal representing the given table. It causes ambiguities when the table name contains a dot (".") character.

988

989 --]]--

990 function class_prototype:get_qualified_table_literal()

991 if not self.table then error "Table unknown." end

992 if self.schema then

993 return self.schema .. '.' .. self.table

994 else

995 return self.table

996 end

997 end

998 --//--

999

1000 --[[--

1001 list = -- list of column names of primary key

1002 <db_class>:get_primary_key_list()

1003

1004 This method returns a list of column names of the primary key.

1005

1006 --]]--

1007 function class_prototype:get_primary_key_list()

1008 local primary_key = self.primary_key

1009 if type(primary_key) == "string" then

1010 return {primary_key}

1011 else

1012 return primary_key

1013 end

1014 end

1015 --//--

1016

1017 --[[--

1018 columns = -- list of columns

1019 <db_class>:get_columns()

1020

1021 This method returns a list of column names of the table used for the class.

1022

1023 --]]--

1024 function class_prototype:get_columns()

1025 if self._columns then

1026 return self._columns

1027 end

1028 local selector = self:get_db_conn():new_selector()

1029 selector:set_class(self)

1030 selector:from(self:get_qualified_table())

1031 selector:add_field("*")

1032 selector:add_where("FALSE")

1033 local db_result = selector:exec()

1034 local connection = db_result._connection

1035 local columns = {}

1036 for idx, info in ipairs(db_result._column_info) do

1037 local key = info.field_name

1038 local value = {

1039 name = key,

1040 type = connection.type_mappings[info.type]

1041 }

1042 columns[key] = value

1043 table.insert(columns, value)

1044 end

1045 self._columns = columns

1046 return columns

1047 end

1048 --//--

1049

1050 --[[--

1051 selector = -- new selector for selecting objects of this class

1052 <db_class>:new_selector(

1053 db_conn -- optional(!) database connection handle, defaults to result of :get_db_conn()

1054 )

1055

1056 This method creates a new selector for selecting objects of the class.

1057

1058 --]]--

1059 function class_prototype:new_selector(db_conn)

1060 local selector = (db_conn or self:get_db_conn()):new_selector()

1061 selector:set_class(self)

1062 selector:from(self:get_qualified_table())

1063 selector:add_field(self:get_qualified_table() .. ".*")

1064 return selector

1065 end

1066 --//--

1067

1068 --[[--

1069 db_list = -- database result being an empty list

1070 <db_class>:create_list()

1071

1072 Creates an empty database result representing a list of objects of the given class.

1073

1074 --]]--

1075 function class_prototype:create_list()

1076 local list = self:get_db_conn():create_list()

1077 list._class = self

1078 return list

1079 end

1080 --//--

1081

1082 --[[--

1083 db_object = -- database object (instance of model)

1084 <db_class>:new()

1085

1086 Creates a new object of the given class.

1087

1088 --]]--

1089 function class_prototype:new()

1090 local object = self:get_db_conn():create_object()

1091 object._class = self

1092 object._new = true

1093 return object

1094 end

1095 --//--

1096

1097 --[[--

1098 db_error = -- database error object, or nil in case of success

1099 <db_object>:try_save()

1100

1101 This method saves changes to an object in the database. Returns nil on success, otherwise an error object is returned.

1102

1103 --]]--

1104 function class_prototype.object:try_save()

1105 if not self._class then

1106 error("Cannot save object: No class information available.")

1107 end

1108 local primary_key = self._class:get_primary_key_list()

1109 local primary_key_sql = { sep = ", " }

1110 if primary_key.json_doc then

1111 primary_key_sql[1] = {

1112 '("$"->>?)::$ AS "json_key"',

1113 {primary_key.json_doc}, primary_key.key, {primary_key.type}

1114 }

1115 else

1116 for idx, value in ipairs(primary_key) do

1117 primary_key_sql[idx] = '"' .. value .. '"'

1118 end

1119 end

1120 if self._new then

1121 local fields = {sep = ", "}

1122 local values = {sep = ", "}

1123 for key in pairs(self._dirty or {}) do

1124 add(fields, {'"$"', {key}})

1125 add(values, {'?', self[key]})

1126 end

1127 local db_error, db_result

1128 if #fields == 0 then

1129 db_error, db_result = self._connection:try_query(

1130 {

1131 'INSERT INTO $ DEFAULT VALUES RETURNING $',

1132 {self._class:get_qualified_table()},

1133 primary_key_sql

1134 },

1135 "object"

1136 )

1137 else

1138 db_error, db_result = self._connection:try_query(

1139 {

1140 'INSERT INTO $ ($) VALUES ($) RETURNING $',

1141 {self._class:get_qualified_table()},

1142 fields,

1143 values,

1144 primary_key_sql

1145 },

1146 "object"

1147 )

1148 end

1149 if db_error then

1150 return db_error

1151 end

1152 if primary_key.json_doc then

1153 self[primary_key.json_doc][primary_key.key] = db_result.json_key

1154 else

1155 for idx, value in ipairs(primary_key) do

1156 self[value] = db_result[value]

1157 end

1158 end

1159 self._new = false

1160 else

1161 local command_sets = {sep = ", "}

1162 for key, mutability_state in pairs(self._dirty or {}) do

1163 if

1164 mutability_state == true or (

1165 verify_mutability_state and

1166 verify_mutability_state(self[key], mutability_state)

1167 )

1168 then

1169 add(command_sets, {'"$" = ?', {key}, self[key]})

1170 self._dirty[key] = true -- always dirty in case of later error

1171 end

1172 end

1173 if #command_sets >= 1 then

1174 local primary_key_compare = {sep = " AND "}

1175 if primary_key.json_doc then

1176 primary_key_compare[1] = {

1177 '("$"->>?)::$ = ?',

1178 {primary_key.json_doc}, primary_key.key, {primary_key.type},

1179 self[primary_key.json_doc][primary_key.key]

1180 }

1181 else

1182 for idx, value in ipairs(primary_key) do

1183 primary_key_compare[idx] = {

1184 "$ = ?",

1185 {'"' .. value .. '"'},

1186 self[value]

1187 }

1188 end

1189 end

1190 local db_error = self._connection:try_query{

1191 'UPDATE $ SET $ WHERE $',

1192 {self._class:get_qualified_table()},

1193 command_sets,

1194 primary_key_compare

1195 }

1196 if db_error then

1197 return db_error

1198 end

1199 end

1200 end

1201 for key in pairs(self._dirty or {}) do

1202 if save_mutability_state then

1203 self._dirty[key] =

1204 save_mutability_state and save_mutability_state(self[key]) or nil

1205 end

1206 end

1207 return nil

1208 end

1209 --//--

1210

1211 --[[--

1212 <db_object>:save()

1213

1214 This method saves changes to an object in the database. Throws error, unless successful.

1215

1216 --]]--

1217 function class_prototype.object:save()

1218 local db_error = self:try_save()

1219 if db_error then

1220 db_error:escalate()

1221 end

1222 return self

1223 end

1224 --//--

1225

1226 --[[--

1227 db_error = -- database error object, or nil in case of success

1228 <db_object>:try_destroy()

1229

1230 This method deletes an object in the database. Returns nil on success, otherwise an error object is returned.

1231

1232 --]]--

1233 function class_prototype.object:try_destroy()

1234 if not self._class then

1235 error("Cannot destroy object: No class information available.")

1236 end

1237 local primary_key = self._class:get_primary_key_list()

1238 local primary_key_compare = {sep = " AND "}

1239 if primary_key.json_doc then

1240 primary_key_compare[1] = {

1241 '("$"->>?)::$ = ?',

1242 {primary_key.json_doc}, primary_key.key, {primary_key.type},

1243 self[primary_key.json_doc][primary_key.key]

1244 }

1245 else

1246 for idx, value in ipairs(primary_key) do

1247 primary_key_compare[idx] = {

1248 "$ = ?",

1249 {'"' .. value .. '"'},

1250 self[value]

1251 }

1252 end

1253 end

1254 return self._connection:try_query{

1255 'DELETE FROM $ WHERE $',

1256 {self._class:get_qualified_table()},

1257 primary_key_compare

1258 }

1259 end

1260 --//--

1261

1262 --[[--

1263 <db_object>:destroy()

1264

1265 This method deletes an object in the database. Throws error, unless successful.

1266

1267 --]]--

1268 function class_prototype.object:destroy()

1269 local db_error = self:try_destroy()

1270 if db_error then

1271 db_error:escalate()

1272 end

1273 return self

1274 end

1275 --//--

1276

1277 --[[--

1278 db_selector =

1279 <db_list>:get_reference_selector(

1280 ref_name, -- name of reference (e.g. "children")

1281 options, -- table options passed to the reference loader (e.g. { order = ... })

1282 ref_alias, -- optional alias for the reference (e.g. "ordered_children")

1283 back_ref_alias -- back reference name (e.g. "parent")

1284 )

1285

1286 This method returns a special selector for selecting referenced objects. It is prepared in a way, that on execution of the selector, all returned objects are attached with the objects of the existent list. The "ref" and "back_ref" arguments passed to "add_reference" are used for the attachment, unless aliases are given with "ref_alias" and "back_ref_alias". If "options" are set, these options are passed to the reference loader. The default reference loader supports only one option named "order". If "order" is set to nil, the default order is used, if "order" is set to false, no ORDER BY statment is included in the selector, otherwise the given expression is used for ordering.

1287

1288 This method is not only available for database result lists but also for database result objects.

1289

1290 --]]--

1291 function class_prototype.list:get_reference_selector(

1292 ref_name, options, ref_alias, back_ref_alias

1293 )

1294 local ref_info = self._class.references[ref_name]

1295 if not ref_info then

1296 error('Reference with name "' .. ref_name .. '" not found.')

1297 end

1298 local selector = ref_info.selector_generator(self, options or {})

1299 local mode = ref_info.mode

1300 if mode == "mm" or mode == "1m" then

1301 mode = "m1"

1302 elseif mode == "m1" then

1303 mode = "1m"

1304 end

1305 local ref_alias = ref_alias

1306 if ref_alias == false then

1307 ref_alias = nil

1308 elseif ref_alias == nil then

1309 ref_alias = ref_name

1310 end

1311 local back_ref_alias

1312 if back_ref_alias == false then

1313 back_ref_alias = nil

1314 elseif back_ref_alias == nil then

1315 back_ref_alias = ref_info.back_ref

1316 end

1317 selector:attach(

1318 mode,

1319 self,

1320 ref_info.that_key, ref_info.this_key,

1321 back_ref_alias or ref_info.back_ref, ref_alias or ref_name

1322 )

1323 return selector

1324 end

1325 --//--

1326

1327 --[[--

1328 db_list_or_object =

1329 <db_list>:load(

1330 ref_name, -- name of reference (e.g. "children")

1331 options, -- table options passed to the reference loader (e.g. { order = ... })

1332 ref_alias, -- optional alias for the reference (e.g. "ordered_children")

1333 back_ref_alias -- back reference name (e.g. "parent")

1334 )

1335

1336 This method loads referenced objects and attaches them with the objects of the existent list. The "ref" and "back_ref" arguments passed to "add_reference" are used for the attachment, unless aliases are given with "ref_alias" and "back_ref_alias". If "options" are set, these options are passed to the reference loader. The default reference loader supports only one option named "order". If "order" is set to nil, the default order is used, if "order" is set to false, no ORDER BY statment is included in the selector, otherwise the given expression is used for ordering.

1337

1338 This method is not only available for database result lists but also for database result objects.

1339

1340 --]]--

1341 function class_prototype.list.load(...)

1342 return class_prototype.list.get_reference_selector(...):exec()

1343 end

1344 --//--

1345

1346 --[[--

1347 db_object =

1348 <db_object>:get_reference_selector(

1349 ref_name, -- name of reference (e.g. "children")

1350 options, -- table options passed to the reference loader (e.g. { order = ... })

1351 ref_alias, -- optional alias for the reference (e.g. "ordered_children")

1352 back_ref_alias -- back reference name (e.g. "parent")

1353 )

1354

1355 This method returns a special selector for selecting referenced objects. It is prepared in a way, that on execution of the selector, all returned objects are attached with the objects of the existent list. The "ref" and "back_ref" arguments passed to "add_reference" are used for the attachment, unless aliases are given with "ref_alias" and "back_ref_alias". If "options" are set, these options are passed to the reference loader. The default reference loader supports only one option named "order". If "order" is set to nil, the default order is used, if "order" is set to false, no ORDER BY statment is included in the selector, otherwise the given expression is used for ordering.

1356

1357 This method is not only available for database result objects but also for database result lists.

1358

1359 --]]--

1360 function class_prototype.object:get_reference_selector(...)

1361 local list = self._class:create_list()

1362 list[1] = self

1363 return list:get_reference_selector(...)

1364 end

1365 --//--

1366

1367 --[[--

1368 db_list_or_object =

1369 <db_object>:load(

1370 ref_name, -- name of reference (e.g. "children")

1371 options, -- table options passed to the reference loader (e.g. { order = ... })

1372 ref_alias, -- optional alias for the reference (e.g. "ordered_children")

1373 back_ref_alias -- back reference name (e.g. "parent")

1374 )

1375

1376 This method loads referenced objects and attaches them with the objects of the existent list. The "ref" and "back_ref" arguments passed to "add_reference" are used for the attachment, unless aliases are given with "ref_alias" and "back_ref_alias". If "options" are set, these options are passed to the reference loader. The default reference loader supports only one option named "order". If "order" is set to nil, the default order is used, if "order" is set to false, no ORDER BY statment is included in the selector, otherwise the given expression is used for ordering.

1377

1378 This method is not only available for database result objects but also for database result lists. Calling this method for objects is unneccessary, unless additional options and/or an alias is used.

1379

1380 --]]--

1381 function class_prototype.object.load(...)

1382 return class_prototype.object.get_reference_selector(...):exec()

1383 end

1384 --//--

1385

1386 --[[--

1387 db_class = -- same class returned

1388 <db_class>:add_reference{

1389 mode = mode, -- "11", "1m", "m1", or "mm" (one/many to one/many)

1390 to = to, -- referenced class (model), optionally as string or function returning the value (avoids autoload)

1391 this_key = this_key, -- name of key in this class (model)

1392 that_key = that_key, -- name of key in the other class (model) ("to" argument)

1393 ref = ref, -- name of reference in this class, referring to the other class

1394 back_ref = back_ref, -- name of reference in other class, referring to this class

1395 default_order = default_order, -- expression as passed to "assemble_command" used for sorting

1396 selector_generator = selector_generator, -- alternative function used as selector generator (use only, when you know what you are doing)

1397 connected_by_table = connected_by_table, -- connecting table used for many to many relations

1398 connected_by_this_key = connected_by_this_key, -- key in connecting table referring to "this_key" of this class (model)

1399 connected_by_that_key = connected_by_that_key -- key in connecting table referring to "that_key" in other class (model) ("to" argument)

1400 }

1401

1402 Denotes a reference from one database class to another database class (model to model relation). There are 4 possible types of references: one-to-one (mode = "11"), one-to-many (mode = "1m"), many-to-one ("m1"), and many-to-many ("mm"). References usually should be defined in both models, which are related to each other, with mirrored mode (i.e. "1m" in one model, and "m1" in the other). One-to-one and one-to-many references may have a "back_ref" setting, which causes that loaded objects of the referenced class, refer back to the originating object. One-to-many and many-to-many references may have a "default_order" setting, which selects the default order for selected objects. When adding a many-to-many reference, the argument "connected_by_table", "connected_by_this_key" and "connected_by_that_key" must be set additionally.

1403

1404 --]]--

1405 function class_prototype:add_reference(args)

1406 local selector_generator = args.selector_generator

1407 local mode = args.mode

1408 local to = args.to

1409 local this_key = args.this_key

1410 local that_key = args.that_key

1411 local connected_by_table = args.connected_by_table -- TODO: split to table and schema

1412 local connected_by_this_key = args.connected_by_this_key

1413 local connected_by_that_key = args.connected_by_that_key

1414 local ref = args.ref

1415 local back_ref = args.back_ref

1416 local default_order = args.default_order

1417 local model

1418 local function get_model()

1419 if not model then

1420 if type(to) == "string" then

1421 model = _G

1422 for path_element in string.gmatch(to, "[^.]+") do

1423 model = model[path_element]

1424 end

1425 elseif type(to) == "function" then

1426 model = to()

1427 else

1428 model = to

1429 end

1430 end

1431 if not model or model == _G then

1432 error("Could not get model for reference.")

1433 end

1434 return model

1435 end

1436 self.references[ref] = {

1437 mode = mode,

1438 this_key = this_key,

1439 that_key = connected_by_table and "mm_ref_" or that_key,

1440 ref = ref,

1441 back_ref = back_ref,

1442 selector_generator = selector_generator or function(list, options)

1443 -- TODO: support tuple keys

1444 local options = options or {}

1445 local model = get_model()

1446 -- TODO: too many records cause PostgreSQL command stack overflow

1447 local ids = { sep = ", " }

1448 for i, object in ipairs(list) do

1449 local id = object[this_key]

1450 if id ~= nil then

1451 ids[#ids+1] = {"?", id}

1452 end

1453 end

1454 if #ids == 0 then

1455 return model:new_selector():empty_list_mode()

1456 end

1457 local selector = model:new_selector()

1458 if connected_by_table then

1459 selector:join(

1460 connected_by_table,

1461 nil,

1462 {

1463 '$."$" = $."$"',

1464 {connected_by_table},

1465 {connected_by_that_key},

1466 {model:get_qualified_table()},

1467 {that_key}

1468 }

1469 )

1470 selector:add_field(

1471 {

1472 '$."$"',

1473 {connected_by_table},

1474 {connected_by_this_key}

1475 },

1476 'mm_ref_'

1477 )

1478 selector:add_where{

1479 '$."$" IN ($)',

1480 {connected_by_table},

1481 {connected_by_this_key},

1482 ids

1483 }

1484 else

1485 selector:add_where{'$."$" IN ($)', {model:get_qualified_table()}, {that_key}, ids}

1486 end

1487 if options.order == nil and default_order then

1488 selector:add_order_by(default_order)

1489 elseif options.order then

1490 selector:add_order_by(options.order)

1491 end

1492 return selector

1493 end

1494 }

1495 if mode == "m1" or mode == "11" then

1496 self.foreign_keys[this_key] = ref

1497 end

1498 return self

1499 end

1500 --//--

1501

1502 return _M

1503